The series follows billionaire playboy Oliver Queen (Stephen Amell), who claimed to have spent five years shipwrecked on Lian Yu, a mysterious island in the North China Sea, before returning home to Starling City (later renamed "Star City") to fight crime and corruption as a secret vigilante whose weapon of choice is a bow and arrow. In the second season, Oliver has vowed to stop crime without killing criminals, using "The Arrow" as his new name to represent that,[1][2] and is aided with by allies, John and Felicity. Oliver's vow is tested when he comes under attack from Slade Wilson (Manu Bennett), a man from Oliver's time on the island who resurfaces with a vendetta against him. Oliver grows to accept aspiring vigilante Roy Harper as his protégé, and begins to receive assistance from Quentin. Oliver also gains another ally, Sara Lance (Caity Lotz), who survived her ordeal at sea six years prior. The season features flashbacks to Oliver's second year on Lian Yu, where he faces a new threat from Dr Anthony Ivo (Dylan Neal), whilst continuing to struggle to survive alongside allies Slade and Sara, and the archer Shado (Celina Jade). The origins of his feud with Slade is revealed.

The series was renewed for its second season on February 11, 2013. The second season received critical acclaim, and averaged 3.28 million viewers each week. The season would go on to be nominated for fifteen nominations in various categories. This season introduces characters from The Flash, which was being developed as a potential spin-off at the time. The season was released on DVD and Blu-ray on September 16, 2014.

Following the destruction of the Glades and Tommy Merlyn's death, Oliver Queen returns to Lian Yu alone as penance for failing the city and Tommy. Laurel Lance is revealed to be working for the District Attorney. Felicity Smoak and John Diggle arrive and convince Oliver to return, informing him that his mother, Moira, is awaiting trial while Queen Consolidated is under the threat of takeover and dissolution by Isabel Rochev. Oliver learns a group of vigilantes, dressed like "The Hood", are killing others as a retribution for the earthquake. They target Oliver twice before kidnapping his sister, Thea. Oliver saves her without killing anyone and leaves the vigilantes for Quentin Lance, who has been demoted to patrol officer. Roy Harper is also trying to protect the Glades, and is rescued by an unknown female vigilante. Using Walter Steele's help, Oliver saves his company and forces Rochev to accept a partnership. Thea reconciles with Moira. Oliver decides to honor Tommy's memory by becoming a hero in Starling City, and finding a new name for his alter-ego. In a flashback, Oliver, Shado, and Slade Wilson encounter new armed men after months of believing to be alone. The newcomers are revealed to be searching some specific graves.

Roy fails to stop a truck robbery committed by Chien Na Wei. When Oliver attempts to convince Roy to stop being a vigilante, Oliver learns that the hospital in the Glades is having its medicine stolen. Oliver sets a trap for Chien, who escapes after having clawed henchman fight him; the police arrive and the two escape. Diggle is revealed to have ended his relationship with Carly. Oliver decides to work with Sebastian Blood, an alderman for the Glades, to bring awareness and help for the people in need, but is forced to abandon his appearance at the charity event to instead stop Chien, who gets arrested. Blood lambastes him in the press for that. The vigilante convinces Roy to stop fighting in his name, but instead provide him intel in the Glades. Afterward, Laurel, blaming the vigilante for Tommy's death, sets a trap for him, who gets seemingly surrounded by the police. In a flashback, Slade advises Oliver not to let his relationship with Shado get too serious. The trio discovers a cave containing the remains of several cranially disfigured World War IIJapanese soldiers.

Oliver assigns Roy to track a woman who inadvertently tries to be a vigilante, which he manages through her connection to a woman named Cindy. Quentin discovers that the serial killer Barton Mathis, whom he arrested years earlier, escaped from prison during the earthquake and is on the killing spree again. Believing the vigilante's claim to have changed, Quentin enlists his help. The team discovers the link between all of the victims. Oliver learns that Mathis has abducted Quentin and Laurel and plans to kill the latter. Oliver saves them before the female vigilante shows up and kills Mathis. Oliver believes that she has a personal connection with him. Laurel states that she must blame herself instead of the vigilante for Tommy's death. The District Attorney announces his intention to seek the death penalty for Moira. She tells her lawyer not to fight it, since she had connections with Malcolm Merlyn that she does not want revealed to her children. The female vigilante kills an operative of Ra's al Ghul, her former master. In flashbacks to the island, a ship starts bombarding Oliver and Slade. Oliver finds himself imprisoned with other inmates in a ship called the "Amazo".

Felicity realizes that the female vigilante has been following Laurel, not Oliver. Oliver manages to ambush her and discovers that she is Sara, Laurel's sister, who was believed to have drowned. Meanwhile, weapon shipments keep being intercepted by a gang leader calling himself "The Mayor", who assaults a gun rally hosted by Oliver and Blood. Cindy is shot in the process; but Roy saves her. Felicity manages to identify the Mayor as Xavier Reed and tracks him down. Oliver recruits Sara to assist him in capturing Reed. Afterwards, a corrupt police officer brings Reed to an unknown location, where Blood, called Brother Blood by his associates, injects him with a green substance that kills him. He orders another person to be brought for the substance. Meanwhile, Laurel develops a drinking problem and refuses help from Quentin and Oliver. In response, Oliver asks Sara to reveal herself to her family, knowing they will stop talking to him for lying. In flashbacks, Oliver is questioned about the Japanese bodies; but when he refuses to answer, he is taken to an interrogation room where he first learns that Sara is alive.

Sara and Oliver are attacked at by a man dressed like Malcolm Merlyn. Sara reveals that the man, Al-Owal, is a member of the League of Assassins, which Malcolm is revealed to have been a member of, and is targeting her for leaving. Al-Owal threatens to kill her family. Oliver manages to protect Laurel, but Quentin refuses to heed Felicity's warning. Sara reveals herself to him and seeks refuge in a clock tower. They seek Oliver's help to stop another attack, with Sara killing Al-Owal and sending a warning to Ra's. Afterwards, Sara decides to leave Starling City to keep her family safe, entrusting her secret to Quentin. Thea and Oliver tell Moira that her secrets will not make them leave her. She agrees to fight death penalty. In flashbacks, after being left adrift from the Queen's Gambit wreckage, Sara is rescued and brought aboard the Amazo, where she meets Dr. Anthony Ivo, who asks her to help him with his experiments to what he believes to be saving humanity. Later, she injures Oliver whilst on the Amazo.

After A.R.G.U.S. agent Lyla Michaels, revealed to be Diggle's former wife, goes missing, Oliver charters a trip to Russia to help Diggle find her when they learn that she was following a lead on Floyd Lawton's whereabouts. Isabel Rochev joins the flight, believing that Oliver is trying to meet with the subdivision of Queen Consolidated behind her back. Once there, Oliver and Diggle learn that Lyla is being held in a gulag. They enlist the help of a Russian contact Oliver first met in Amazo. Following their plan, Diggle is arrested and sent to the gulag to rescue Lyla. Oliver has a one-night stand with Isabel. Diggle finds Lawton among the inmates. The pair is forced to team up to save Lyla and escape. Afterward, Diggle lets Lawton go for helping him save Lyla; in return, Lawton reveals that he was contracted to kill Diggle's brother by an organization called H.I.V.E. Diggle and Lyla get involved again. In flashbacks, Ivo reveals to Oliver that the Japanese soldiers were transporting "Mirakuru", a secret serum for human enhancement. Later, Sara plays Oliver into revealing that Shado and Slade are still alive. Oliver realizes Sara has betrayed him by revealing his identity to Ivo.

It is revealed that The Count escaped from prison, where he was transferred after recovering from his psychosis, during the earthquake. Afterwards, The Count begins poisoning civilians with the Vertigo drug; Diggle and the Assistant District Attorney are among the infected. The Count reveals in a broadcast that the cure to the sickness is to take Vertigo. In the court, Laurel uses an affair between Moira and Malcolm to cast doubts on Moira's defense. Felicity is captured by The Count. In order to protect Felicity from being injected with Vertigo, Oliver is forced to kill The Count. Meanwhile, Blood, revealed to have hired The Count to kill the vigilante, now known as "Arrow", is informed that one of his test subjects named Cyrus has survived his injection, feeling "stronger". Ultimately, Moira is exonerated by the jury; she later learns that Malcolm, alive and well, had rigged the trial. He also reveals that he now knows Thea is his biological daughter. In a flashback to the island, Shado and Slade rescue Oliver and Sara, after Dr. Ivo and his men travel to the island to locate the Hosen, the stone arrowhead, which contains coordinates to the wreckage of the Japanese submarine.

When a masked thief with superhuman strength steals a centrifuge from Queen Consolidated, Central CityCSIBarry Allen arrives to help the investigation. Later, he reveals that he is searching for super-powered beings in the hope that he will find the murderer of his mother, and exonerate his father for the accusation. Oliver realizes that the thief was enhanced using the same serum that Ivo was searching for. Roy starts to help Cindy find her missing friend, who was a failed subject of Blood's experiment. Oliver shoots Roy in the leg to prevent him getting further involved. Oliver tracks the thief, but is injected with an unknown toxin. In order to save Oliver's life, Felicity reveals his identity to Barry to help find an antidote. Meanwhile, Merlyn puts pressure on Moira to tell the truth to Thea. Moira instead contacts Ra's, who wants to kill Merlyn for breaking the League's code by destroying the Glades. As a result, Merlyn leaves. In a flashback to the island, Oliver and Shado find the Mirakuru, but when they inject it into Slade without the required sedative, his heart stops, just as Ivo arrives with his men.

Barry manages to save Oliver's life. Barry and Felicity are able to identify the thief as Cyrus Gold and locate him. While continuing to investigate the death of Cindy's friend Max, Roy is captured by Cyrus and brought before Blood, who injects him with the Mirakuru, which kills Roy. Oliver arrives and kills Cyrus, simultaneously destroying the centrifuge and the remaining serum. Oliver revives Roy, but worries that the serum may affect him negatively. Slade is revealed to be alive in the present and the one orchestrating Blood's work; he orders Blood to leave the vigilante alone, so that he can deal with him personally. While Roy recovers at the Queen mansion, the serum injection heals the arrow wound in his leg. Barry leaves a domino mask for Oliver, to better hide his identity, and returns to Central City. While in his lab, Barry is hit by strange lightning created by an accident at the new particle accelerator lab.[12] In flashbacks, Ivo tells Oliver to choose between Sara and Shado. When Oliver steps in front of Sara, Ivo kills Shado, but flees when Slade turns up with super-human strength and kills his men, leaving the Mirakuru behind.

Oliver continues his search for the man in the skull mask while Felicity has been traveling to Central City to visit Barry, who is in a coma due to being hit by the lightning. Serial bomber Mark Scheffer, who goes by the name "Shrapnel", begins setting off bombs across Starling City as an anti-government movement. Blood begins his campaign for mayor and decides to organize a Unity Rally for the city. Scheffer targets the rally, but Oliver is able to stop Scheffer, who is arrested; and the bombs are disarmed. During the commotion, Thea witnesses Roy using his new strength and confronts him. As the vigilante, Oliver makes an alliance with Blood. Meanwhile, Quentin starts looking for the inside man in the police department associated with Cyrus. Investigating Blood, Laurel visits a mental institution, where she finds Blood's mother, who reveals that he killed his father and put her in the institution to cover it up. In a flashback, Slade experiences adverse effects to his mind and personality due to the Mirakuru, which leads to him secretly separating from Oliver and Sara.

Blood visits his mother and kills her after learning that she told Laurel the truth. Oliver continues his search for the man in the skull mask and receives help from Laurel, who suspects that it is Blood. Fearing that he will be discovered, Blood has Laurel arrested for drug possession by his disciple, Officer Daily. Afterwards, he has her kidnapped to lure Arrow out. The latter comes to rescue her; but during the fight, Laurel kills the masked man, who is revealed to be Daily, unknowingly throwing suspicion off Blood. Laurel is cleared of charges, but is fired because of her addiction. Slade, now wearing a specific suit and mask, is revealed to have planned for Blood to get intimate with Laurel in order to hurt Oliver. Meanwhile, Roy and Cindy attempt to use his new powers to stop a murderer, but Roy goes overboard and puts the man in the hospital. Arrow convinces Roy to train him in order to control his new powers as well as his change in mental state. In flashbacks, Sara initially considers an offer from Ivo to return the Mirakuru for safe passage off the island, but changes her mind eventually.

Ben Turner escapes from prison with assistance from H.I.V.E. associate Milo Armitage, who also pays him to steal a prototype of Malcolm's earthquake device. Oliver tells his teammates that Slade got angry when he found out how Shado died, as Slade was in love with her, and attacked him, which ended with Oliver putting an arrow in his eye. Arrow tracks down the device and is forced to reveal his identity to Roy in order to get his help in destroying the device. Meanwhile, Laurel learns that she may be disbarred because of her addiction and spirals further out of control. Oliver convinces Sara to reveal herself to Laurel. Walter convinces Moira to run for mayor against Blood; and she states that it is necessary for the campaign that it not be revealed that Thea is not Robert's biological daughter. Moira reveals that her obstetrician knows the truth and he needs to be dealt with. A.R.G.U.S. agent Amanda Waller propositions Turner to commute his sentence in exchange for him joining a "squad" she is forming. In flashbacks, Oliver stops Slade from destroying Ivo's freighter with Fyers' missile launcher. They plan to capture the freighter.

Nyssa al Ghul, the daughter of Ra's and a member of the League, arrives in Starling City to convince Sara to return to Nanda Parbat with her. It is revealed that the two have a romantic history. Sara refuses, so Nyssa kidnaps her mother and threatens to kill her if Sara does not agree to return. Instead, Sara drinks snake venom. Arrow arrives with an antidote and Nyssa releases Sara from her obligations to the League. Meanwhile, as Moira begins her political campaign, Felicity discovers that Thea's true father is Malcolm and reveals it to Oliver, who decides to support Moira's campaign publicly while privately renouncing their familial relationship. Although Sara is welcomed back by her parents, Laurel shows displeasure to her by angrily yelling at her. Sara later joins Oliver; and they have sex. In addition, Slade decides to deal with Moira's campaign against Blood. In flashbacks, Sara and Laurel get into an argument after the Laurel tells her that she and Oliver plan on moving in together; and Sara agrees to meet Oliver at the docks. Later, Laurel and Quentin watch a news report about the Queen's Gambit gone missing. Moira informs them about Sara.

William Tockman orchestrates a heist of an electronic device that will allow him to access any bank vault. Oliver and Sara start working together to stop him, foiling one of his robberies. In response, Tockman uses the device to hack into the computer servers at Oliver's hideout and overload them so they explode. Felicity, feeling left out with Sara now part of the team, attempts to bait Tockman into coming after one last heist. Oliver, Sara and Diggle arrive in time to protect Felicity, but she takes a bullet to save Sara before knocking Tockman unconscious, feeling part of the team again. Meanwhile, the Lances attempt to have dinner together and it is revealed that Sara and Oliver are in a relationship, much to Laurel's anger. Later, Laurel reconciles with Sara and attends an A.A. meeting with Quentin. Slade makes his presence known to Oliver by coming to his home and meeting with Moira. In flashbacks, it is revealed that Sara befriended Cindy after promising her dying father, a pilot shot down while flying over the island, to look after her. From the plane, they recover a parachute, which they plan to use to take the freighter.

Oliver, Moira and Thea give Slade, who has funded Moira's campaign, a tour of the house. Sara and the rest of the team are notified and arrive to assist Oliver, forcing Slade to leave without engaging. Oliver deduces that Slade is the one controlling the man in the skull mask, and attempting to create more Mirakuru. Slade informs Oliver that he is there to follow through with a promise he made to Oliver on the island. Later, it is revealed that Slade used the tour to plant cameras throughout the house. In flashbacks, Oliver, Slade, and Sara are able to board the ship. Sara frees the prisoners, while Oliver and Slade go after Ivo, who reveals the truth about Shado's death to Slade. Slade turns on Oliver and imprisons him on the ship as Sara and the other prisoners escape to the island. Slade takes control of the ship, amputates Ivo's right hand and reveals to Oliver that he kept the Mirakuru, having had Sara and Oliver destroy an empty box previously, and promises Oliver that he will not kill him until he has first made him suffer the loss of those he loves.

In a flashback to years prior in Afghanistan, Diggle and Lyla lead a group of Afghan villagers when a wanted man, Gholem Qadir, is identified among the group. During an ambush by the rebels, Diggle saves Qadir's life. In the present, Diggle and Lyla are called upon by Waller to lead her "Task Force X", also known as the "Suicide Squad", which consists of Floyd Lawton, Ben Turner and Mark Scheffer being used as expendable assets. The Squad is sent after Qadir, who has developed a deadly nerve agent. Scheffer attempts to escape and is killed. After saving Qadir's life again, through a faked assassination attempt, Diggle is invited to Qadir's home for a party. Once there, Lawton locates the agent and is used as a target marker for a drone strike on the house. Diggle decides to save Lawton while Turner kills Qadir; as a result, the drone misses the house and a Navy SEAL team is forced to destroy the agent. Oliver is forced to go to Waller for help, revealed to have interacted with her before. She tells him that A.R.G.U.S. has been tracking a new mercenary called "Deathstroke", whom the pair realize is actually Slade.

Oliver and Sara assist a police raid, and in the process help capture Frank Bertinelli. Oliver quickly realizes that Helena will return to kill Frank once she hears the news. Laurel is asked to return to the District Attorney's office to try Frank's case. Helena shows up at the courthouse and takes hostages in exchange for Frank. Sara goes to the courthouse to rescue Laurel, but Helena overpowers her and demands that Oliver deliver Frank in exchange for Laurel. Oliver complies; but Frank is killed in a crossfire with the SWAT team; Quentin ultimately arrests Helena, after Sara stops her. Helena tells Oliver that he was right to discourage vengeance. Despite bringing Laurel to have been just a ruse for Helena, the District Attorney rehires Laurel to avoid scandal. Roy breaks up with Thea on Oliver's advice. Slade drives by and gives her a ride. In flashbacks, Slade demands Sara return Hendrik, one of the escapees who can fix the engines of the ship, by threatening to kill Oliver. Sara and the other escapees prepare to send Hendrik back against his will while Slade has the same tattoo on Shado's back drawn on Oliver's as a reminder.

Slade kidnaps Thea. Oliver gives temporary CEO status to Isabel in his absence and later reconciles with Moira. Isabel uses her temporary power to convince the board of directors to make her position permanent, thus allowing her company to take full control of Queen Consolidated. When confronted, Isabel reveals that she has been working with Slade the entire time, and tells Oliver where Thea is being held. Oliver arrives; but Thea has already been freed—her kidnapping was a diversion from Slade's real plan to free a group of convicts to be used as test subjects for the next Mirakuru trials. Thea confronts Oliver and Moira, saying that Slade revealed to her that her biological father is Malcolm. Quentin is arrested for aiding the Arrow. Roy leaves Starling City. Moira's chance of winning the election increases as shown in the polls. Isabel tasks the company's scientific division to work on Mirakuru. Slade, who is announced a fugitive, visits Laurel and reveals that Oliver is the Arrow. In flashbacks, Sara attempts to use the trade for Oliver as a moment to kill Slade, but fails. Shado's hallucinations convinces Slade to spare Oliver and Sara, leaving Ivo with them on the island.

Oliver's team destroys Isabel's lab so that Slade cannot use it to mass-produce the Mirakuru. In response, Slade steals an electronic Skeleton Key from Oliver's hideout. He uses it to steal a bio-transfuser from a S.T.A.R. Labs facility that Caitlin Snow and Cisco Ramon work at that will allow him to transfer the Mirakuru-infused blood to the freed convicts. Oliver tracks Slade and discovers that he has kidnapped Roy and is using him to transfuse the blood. Oliver rescues Roy, and Isabel, who is revealed to had been involved with Robert previously, is critically shot. Later, Oliver reveals there is a cure for the Mirakuru and Felicity enlists the help of Caitlin and Cisco. Slade's super soldiers gather and he uses his blood to heal and empower Isabel as well. Meanwhile, Laurel discovers that Sara is the female vigilante. Laurel tries to tell Quentin about the Arrow's identity; but he dissuades her from telling anyone. Laurel later blackmails her supervisor into releasing and reinstating Quentin. Thea leaves home even after Oliver reveals to her that Robert knew about her non-paternity. In flashbacks, Oliver kills Ivo on his request after Ivo tells him the location of the Mirakuru cure.

Roy goes on a rampage, overwhelmed by the Mirakuru and no longer thinking for himself. During a fight, Oliver's leg is significantly injured and Roy escapes. Sara decides that Roy must be killed; but Oliver disagrees. Roy comes to Verdant and Oliver uses the opportunity to inject Roy with pit viper venom to knock him unconscious and keep him sedated until a cure can be found. Sara decides that she is not good enough for Oliver and leaves the city to find a friend. Meanwhile, Thea continues to distance herself from her family; so Moira decides to drop out of the mayoral race. Oliver dissuades her; and she reveals that she has known Oliver was the Arrow since last year's earthquake; and that she is proud of the man he has become. Moira, Thea, and Oliver are attacked by Slade, who tells Oliver to choose between his mother and sister like he did with Sara and Shado. When Oliver refuses, Moira sacrifices herself and is killed by Slade. In a flashback to seven years prior, Oliver reveals that he got a young woman, Samantha Clayton, pregnant; so Moira pays Samantha to tell Oliver she had a miscarriage and leave Starling City.

When Oliver doesn't show up at Moira's funeral, Diggle and Felicity enlist the help of Amanda to track him down. They find him in a secret hideout, where he reveals to them he intends to surrender to Slade and face his fate in order to protect everyone else. Meanwhile, Isabel returns and shuts down Verdant, forcing Thea to make a decision to leave Starling City, and Sebastian is sworn in as Mayor. Diggle and Felicity inform Laurel of Oliver's intention to surrender to Slade. Laurel confronts him, revealing that she knows he is the Arrow and telling him that Sebastian is working with Slade, and that she has documented proof that Sebastian knew Slade was going to kill Moira. After confronting Sebastian, Oliver decides that they have no choice but to kill Slade's Mirakuru army. Slade's army, Mirakuru soldiers wearing Deathstroke armors, is wreaking havoc on the city, cornering Oliver and Laurel. Diggle meanwhile is confronted by Deathstroke armor-wearing Isabel. In flashbacks, Anatoly repairs the Japanese submarine and he and Oliver prepare to attack the Amazo; but Oliver gets a distress signal from Sara outside the submarine.

As Slade's men continue to terrorize the city, Felicity and Diggle outwit Isabel and escape. S.T.A.R. Labs makes a cure for the Mirakuru, but Slade sends men to acquire it before Oliver. Finally trusting Quentin, the police force pledges to help the Arrow stop Slade's men and Quentin is reinstated to lead them. Slade reveals to Blood that he plans to destroy the entire city, people and all, in his quest for vengeance against Oliver. As a result, Blood steals the cure and gives it to Oliver in return for help saving the city. For his betrayal, Slade has Isabel kill Blood. Oliver tests the cure on Roy after Amanda reveals that she intends to bomb the city at dawn to prevent Slade's men from attacking the rest of the country. Meanwhile, Sara returns and saves Laurel, who gives her the alias "Canary". Malcolm saves Thea from an assailant and tries to convince her to leave with him; but she shoots him. In flashbacks, Oliver boards the Amazo to rescue Sara, who was captured by Slade, with specific orders for Anatoly to destroy the ship if they do not return within an hour. However, they are both captured by Slade.

In flashbacks, the Amazo sinks as Oliver planned. He presumably kills Slade while Sara disappears overboard. Later, Oliver awakens in Hong Kong, where he meets Waller. In the present, the cure works on Roy. Sara arrives with Nyssa and the League to provide backup for Oliver, who gives Roy a red mask. They confront Slade and Isabel at Queen Consolidated. Nyssa kills Isabel, and tells Oliver he needs to kill Slade, who escapes. Meanwhile, Diggle and Lyla free the Suicide Squad members and enlist their help to try to stop the drone strike. Quentin is seriously injured. Thea meets up with Roy; but when she finds a bow and arrow, she loses trust in him and leaves Starling City with Merlyn. Oliver and his team successfully use the cure on all of Slade's men. Oliver tricks Slade into kidnapping Felicity, believing she is Oliver's love. With Slade distracted, Felicity injects him with the cure. Oliver defeats Slade and Waller calls off the strike. Slade is locked in an underground A.R.G.U.S. prison on the island and Sara rejoins the League as payment for helping the city. Lyla is revealed to be pregnant from Diggle. Quentin collapses as a result of his injury.

On February 11, 2013, The CW renewed Arrow for a second season for the 2013–14 season.[39]

A backdoor pilot for The Flash was originally going to be the twentieth episode, but due to the positive reception of Grant Gustin's appearance in the eighth and ninth episode, executives at The CW scrapped it in favor a traditional pilot so that it gives the developers more time to flesh out the character in addition to receiving an increase in the budget.[40]

Emily Bett Rickards, Colton Haynes and Manu Bennet were all promoted to series regulars.[41]Jacqueline MacInnes Wood, who originally played Sara Lance in the pilot, did not return and was replaced by Caity Lotz.[42]

In the second half of the second season, Oliver replaces his "paint" mask with a domino mask, similar to one worn by the character in the comics. The change is addressed on-screen, with Kreisberg saying, "He doesn't just put on a mask. It's actually a big plot point in an episode, and there really is a story behind, not only the need for the mask but also who provides him with it."[43] On adding the mask now, Kreisberg stated that, "Conceptually, it was something we wanted to do because Oliver himself is evolving as the Arrow—from vigilante to hero, sort of from Arrow to Green Arrow—and we wanted to see that progression in his costume as well. As Oliver is embracing being a hero, being a hero means stepping out of the dark and being more of a symbol, so he has to take steps to conceal his identity more."[43] He added that it will "allow the Arrow to interact with people who don't know his identity in a much more organic way than having him constantly keep his head down."[43]

Costume designer Maya Mani put together roughly 50 mask options for the producers. Kreisberg said, "What's so wonderful about the design that Maya came up with is that it really is very simple, and it feels as if it’s been part of his costume since the beginning...once we finally had this mask and put it on Stephen [Amell], even Stephen was like, 'This is the right one.'"[43] In the episode "Three Ghosts", Oliver receives the mask from Barry Allen, who is able to create a mask that will help conceal his identity, while still being functional and allowing Oliver to see clearly.[44]

Arrow: Season 2 was released as a 5-disc DVD set and as a 9-disc Blu-ray and DVD combo pack set on September 16, 2014 in the United States and September 15, 2014 in the United Kingdom. The DVD and Blu-ray box sets contain additional features, including making-of featurettes, deleted scenes, gag reel, and highlights from the Paley Fest.[45]

The second season received favorable reviews. Jeff Jensen of Entertainment Weekly gave the first half of the second season a rating of B+, saying, "Arrow possesses an intelligence that shines through its TV-budget production values, which aren't too shabby. The writing is adult and witty, the action is exciting, and Amell holds the center with well-cultivated ease."[46]The A.V. Club's Carrie Raisler gave the first half of the second season a rating of A-. She said, "Arrow [has] officially established itself as one of the most satisfying shows on television. The most satisfying thing of all is that it did so by respecting its characters... [Arrow respects] the character’s comic-book roots in its overarching plotlines, all while using the network-appropriate soap-opera stories to do the heavy character lifting."[47]